Reflectance and complex refractive indices in the infrared for aqueous solutions of nitric acid

Near-normal incidence reflectance spectra relative to water were measured throughout the 310 to 5000 cm−1 spectral region for 0.5, 1, 2, 4, 8, and 15.7 M aqueous solutions of nitric acid. Spectral values of the complex refractive index N (ν) =n (ν)+ik (ν) of the nitric-acid solutions were computed by use of Kramers–Kronig techniques. Values of N (ν) are presented in graphical and tabular form. The spectra were further analyzed to determine the central frequencies, half-widths, and strengths of infrared bands due to intra- and intermolecular vibrational modes of liquid water and intramolecular vibrational modes of NO3−, H3O+, and HNO3.